SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '791100f82bea395a7466c2fef7bc59396c62540635ef2939850fb6005d33f56f' 
  AND token = 'SegND09WkAjxN/6vICvJLvamZCYxtDGRfUr0ZBcFd6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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