SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57b04cc1e8256e4eb5f9e825f95d25856bda848ee98976715af544f8c7199480' 
  AND token = '+dUd9eSzw4+51S7twQ9EC+bn8Vp15e8l9K/Zg9n61qs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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