SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8e1751e6bb5cbcccaae48124681d06361cacf973c4023071d139e7d8f3027c6' 
  AND token = 'zkg7ubghoj0fyraokLre8bdDKFjZ96AP+y/TFAKogBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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