SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f246b87daf6359e212367ec89663b8a45e1bb10fd98e248d54cdca66210d5716' 
  AND token = 'UknDWjoSXNYlD4nGe7KcMvYH6bu9FxZitTCiT77mqTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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