SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd8c797c014ab6850fdd6d3da330bd8b79588526d73717f0ebff7edad269f86f' 
  AND token = 'TW3ucmAJ7kUhgU+EAG3rq2iAdYVprY7CbWDRWYB0gjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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