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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71d1abc58c3bae59d0b510981c0caf4483d0cad3ba50a5a5e9443b98cd8dca64' 
  AND token = 'VcpX5mrq2haTNkiEmJB2V5AW4wXCOwtui/p/AkaDmTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}