SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1a667ef49f74321da63b59cab82e5881f6be2cc5349dc2c91deb15440539e97' 
  AND token = 'c7X6wzxSaUWMN3MDIJZXxBRsnbE4Btt0+DhMCV5gCEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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