SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5e820b5019d6e54c083a28aa8ebfb05005ed1b0243c614e7c8c058f6a972b05d' 
  AND token = 'gkQasJjPxcmQu37z03hsXEeUueOfYLJ5wGhKv///yl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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