SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7d098df0d9017d1460317b39c8bf7a4778e1d682c8e287304e67bf4ffcbc510' 
  AND token = 'xyQzLGxWY+z9TTgoBuDC928CJhA4h/ECz/wRrfw5N5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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