SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '264afb608373a09bb4dd758593f30b81764566bbd44577591bef4833a247615a' 
  AND token = 'HB5J7vTkP2PS6pzUtWwGlVEw/Flg8/LDgtBVG5DqIxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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