SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f87cb153afd546107153a71ffdf7deb075f6e4123a6d588bb053247a8975ce84' 
  AND token = 'pbBnyDVS5tFZg4WYUw+VvEXW5bDgXBarMtrQlnIg1jA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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