SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec1f1701dc35a74afa72a8c652210199daf59475e80b91b0379fc53f56c36e4b' 
  AND token = 'lkm73co/nr9TLzu5kflXLgLRfEGq/eGDJMSk5PbRuiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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