SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5083dd7500d4c7cadb728fb185dd9f1ca041616efb30a7c5b02176518db5192' 
  AND token = 'SQJO71rCzwQJKwy8yv8PtqsgpAY9rhpIcKL+3RIdx9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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