SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2b7fd7717eb8752ba02baca254538f968a4fe77c88e6aebf4d07d1e5eead8c3' 
  AND token = 'qPrCITQYXFb0UJzQpUc5f4OcxtfZ0wzrSfGxAdP+OfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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