SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0532ed423b483ff5a2b638b229bb4aa7b51aee4127795d5a1f9a49500534f3b2' 
  AND token = '+k0xrQ1GyIkfz0m/+N3aalEeyqrVd4NgrBkispMlYsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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