SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df09076247efc1e748ef9ac38ed5251b9f605a258ac7851f59fe7e3910335970' 
  AND token = 'n4qKVALwhZd6YwCWyMk6yvygQXAnCLkP02m4nNZJvpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}