SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e773f427639aa312a811192dd1faf7ba760fe37e4fa6fb5625735c3212b3d6bb' 
  AND token = '08iRnDNzzsSOZ18L5Vgxv8Q/R5cpVtaVm1d1l3U0pJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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