SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dee553ec8e8500ed7a7af87051271a9cb54b35827380dec81e1add597adc79eb' 
  AND token = 'GSZwy79OA5CxPmHyHnqBdcAsn/6z1IEbfPXjVCdR6RM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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