SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd08b073901f152cbf3303ff2639116584314f499d15a752b774335e73381cb2f' 
  AND token = 'Oy62cfztKZjQatIj/4IovzmwZ8/O9U56Fx5OvwyyM0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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