SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f8dec472faf845a9b6e5b3d8a93e844b495d1c31c06e57603ac6312cdfdf36c' 
  AND token = 'jOjvGRkzwtwy4jcWYqYGB48bgMUEZWTpbjAGlUVWjVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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