SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c20630b39af6380aed262d90c90300811129b5ad357ef0ecc584dc27f0d372e' 
  AND token = 'E39v+DmL6SdLiCSrxhWt5OHs0md9EnNXSSLxgYriw7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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