SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71ef48f1d08b62b1624d5d91c469a80c426a999848c42b548742bdd46af5563e' 
  AND token = 'H/bFQYS+VvZS9h7afmSbiM3yQ7RRYF6X9CzfXrlWJLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}