SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fa6a4634f0237ad5372341bda756ef343887e0b453822522168a47c441750b7' 
  AND token = 'QdtzPO+nK2e7c4gbjtEQWzhDCEOqk8HAZyQZx7suoMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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