SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1c97a808699f0d6d237e52b1916fb0770b40b025f1e4a828d56b96e671b7ca2' 
  AND token = 'Zmak3K0jX3dHBpMAWKxRqWiyADfbiD59ByWgs+YtZKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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