SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d5dbfe98835a1ad0fc2beece3cb67e7e4b88e6ecf1fe466dad734325ea3321a' 
  AND token = 'OCGgiEYCUyi9Jb7mPzZq/a7gF8OpoCRrxoiVLC7w470=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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