SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf0196741744f823994a21470c70b80f0a657608fa8c01a630f26dd134ac509b' 
  AND token = 'MjfPkvtqf3G5d0buzg0M47FnZYogZJc51JWi/9mGFPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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