SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dbff5bf5730859295ee784efd2d44406349b160bc40d2cf2e0f5aaac44262d4' 
  AND token = 'clFa6Ut2FQdJBjUiZiIq3YMsZcQBE5P5/WzCGyMamY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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