SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '870d9130a982b01135ea1b481b5056c0194e80c5354ef7f83a8a1e9eceb456bb' 
  AND token = 'phcy8H5ADIgnV1lCZC2D+ovdRjnSlQnKDY+zw+JPK2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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