SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'dcfb420c23514c054624657617346f71e882f47757d90b590918e6401f5a90d1' 
  AND token = '4jhiEhr8WuFgxNK7VGCs5PeJrqUvnv1GK595VfRRV3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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