SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b92fd898a5d0e0e46fa2bce3bef8d9b4c166c089acdcafb135a6dfdd8dc68ae7' 
  AND token = '0eRH6DaCIGI5mQ9Xmd2OHaxICk9bjRwkBdaJT2kfkoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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