SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d5156ff3e45718ad7df8ad36c7547c4d40bcf90ad30746f429875ec8187866e' 
  AND token = 'fdk7NeEPt6JqT6LUAMBjuDKjAWvyNIh9iU/foHRCuT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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