SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c11944a0020f34a4f695720de6e0e346d8470c4c77c5afb5a09e08a24afe186d' 
  AND token = '7jYrvUFCFBdblVQ90gKmJpxCw5vTZbqIbNSKrNfIRuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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