SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35e87b7a25758414f206b7ba8cd60aaa144cf38f01ef5cf3a1e8cc278f598282' 
  AND token = 'ZY5UPvxoEoLB3j6fO4lrXyAz+qI8rGQI/qme/bKJ/ZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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