SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a9f807dfc529a85dcfdf31153e9d4e8edeea31d25a0a110e4057417aaa355f2' 
  AND token = 'jKoxkPTmr5iBfkGDMCEZJDgKt7xdDxiBcSfJC0CUrGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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