SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a441a362f45cbc5fe08d0f1ffae03278056506a152be361d5a59376fec97b12f' 
  AND token = 'jH50KsG4Pgp8fj8EhomXQSi+xnCayge32kDRuQFbGhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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