SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b596dad9c3f884791a891fa239cfa5158759f70c8533be56c9f143ec07eefbf2' 
  AND token = 'N3uS/ui171UJTnm/IeDZIOnJPyG0gKdOxnJxr15amTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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