SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'de4a291a8f8be352b41b94322324d17cda7ef791e66707d02c0717cb5b355bf5' 
  AND token = 'xyiKtWKGBG39uUC/X6NnYSWwbGqWTr5n+3nksWjYpP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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