SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f73e580b51c8941472ef2b13b81a2f974080c182760d2117494e7967453145c9' 
  AND token = 'qpAOfx7rz9u/OcF7GkbsYqEqppMfVIso9x59erpJ8wg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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