SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b11d86d5233bdf159471a3799bdf42656411433531ea97f0deda27f5988cd88' 
  AND token = 'eUut69GucJijaMWpICD+qBImpFV/BuO+hNoAZljgbcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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