SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d74b3d79be354829f693357c6ac6de2838f4b21c6d41797334e6bc5a2fb2336' 
  AND token = '1ASJLDVlZzQ17Egv5hqdJYDjHBGDfYGNo5onKK+iJKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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