SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b99f133e7b9b1a82c23bb200cf6813a019ea4e4e75f0a05e196755251f4fd7d1' 
  AND token = 'ODAVJzBzPfKxH9qbfORMQPZPHJH2XCUk+CTYD8VbSNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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