SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cb3baafedd6ffe9476975f5b0e016215668480a1e15d72d14ba878cf390578e' 
  AND token = 'xxYUuZBYeNHZAQ9YYyo2KbukeNqRVFqd9QD61kjA07M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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