SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecc528a19f633a53a1b750628d97aa8e6f81c723941aff8828be964b93670d0e' 
  AND token = '5IixUh+D6gAxVFYdM1XXs+YUOUdISy1Q5B5jGL7ws3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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