SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9c7f455e0e82febcdd201183f18f443824434f748dd9c4365a82f5018b228dc' 
  AND token = 'IR9cTu0PgQewHYYaafLaeKuNPy7D0xysl5+JPc1TpUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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