SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78535498c78188cb480bcc2761801ebc95d3ebfe4f4ec2a67d4c281dce5f107f' 
  AND token = '2VYKPCXKZbvmrSMlBsLItR7eerpOzSHTjqKbNG1Cuzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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