SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ef97a133df47c4941e892ff27727340b92aad28e8223137c98e6cd624af9ae9f' 
  AND token = 'GA6dhDZwOUJ6RvMX9jeQcNyj3L5g9uYSSzGSs2xrquM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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