SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b65ad965af39a2fb77a5e0e9d972ac4bba9a7f0937405c70f0bc81d9f73c8c3f' 
  AND token = 'XiYKVihhQSv+K71+MjML7bjivUXDcEdgGuHWUwVw/2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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