SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1f0b8374982a47714de573871136935950c58f7e488754ec225b87ac26bf972' 
  AND token = 'amXYCPRqEkbM8AA4lJLiHDG2kRZkeJOT3WAkNsNYBLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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