SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e918ab3c3642aa342ba6b305faea8320d20096c35c4153880b9bfaf59f20cb36' 
  AND token = 'go1z1GCJqxmCuMNk4zm7sIojJWlqtLF+uGGDQTVV4/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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