SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b3a4980118b8eeead22b2bda9a2b7105fe845aaccfc1251f25dc70ca7963ff3' 
  AND token = 'gvCY3hthNVjeu1CAGbMrYCQ2xS5INw8n6XnpWKoxcmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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