SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a1db952d7bf7964e0d075a5ade056e9c2e2bb7475a91bffa2be2a78700d8e9f' 
  AND token = 'j0tuvvTBFjYs+YCqSJ+zEeku2ZT2nnG0TnSrhISZbQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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