SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '271d6f53b823cc64b49db14577314770d8b3060a40a19529a67126e3cf9a9f7d' 
  AND token = 'hWaH1mzUbKaduaCvlTsQKJVUcSPSOh3SIV0vkkK3GrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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