SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '962d357cb382f65d2d2511238a0cd7e4d08dac0e7eff7f20b41af388cc746ddc' 
  AND token = 'gFwol38jsDrIOlL0bND09tHMhWJVDOp/XBdQded+QgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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