SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '532f73c78ae3d2e4afa60f317f805ae9c7b28b6c2cd87e80f23054b1c31cadc2' 
  AND token = 'ZqDBuJ1gLwZFVmT+Ewnl7J/d6WwVP9RLXGVTLMahShE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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