SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb2057feb93bc0fa372697744d09fed5cfd946d2b5d60b2d23fd88e11d7fc3e2' 
  AND token = 'A2esmcZbtha1WcioMYXAhkFfuI8wilgPkuNoNCDf/f4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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