SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87f0a8e811e7d10eaf9d6d4f8bbde21bffb5844eca458206d46279eba3835f1a' 
  AND token = 'KfcKwZjBoX34VPB3s6siXF5hLlKjALvAYi+qJhfYQAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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