SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd563d7b55011afc4f72a1562146054ad57dbdc9f12f33d60b7dc3afafe8861bd' 
  AND token = 'PIZkwbq9LB+XI2XDApZE5S2UgoclfgYMvsVNxRUKKJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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