SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50c60243a0b285946de054cddd78d570169427e96aca8dea52ddfbe400884d65' 
  AND token = 'AzLKYZEJ/d5oaav6jPjUb6eJDvt9zJlsAVFGTs80yP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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