SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20483d0a9de7e07016ee025e94125c24662d6a1721a3c28393348b6c42fe3dcc' 
  AND token = 'YIRMWQDfaRQZyDdUux/UERTdgOPyrGzRtRaq8XQ5zzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}