SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee81e64de7f399c51f3ab7a5b8067b9784a4521b3b7b975e707ee91a2a49ece8' 
  AND token = 'pmqgDCFNdEZE14EialyQVrQDfAfryBaxshqXYMoIz6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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