SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce49d7595c66b0e793b8d4316773ea43570db6f392e0b435a1becbea4a8bce81' 
  AND token = 'Z2UplqEbEEQuZIoQrHk2TEW9wJpyiWB6GQLOzznxspE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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