SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b58d12a2efa09b61dbaef4eb25934fd0531abb7fcea938cf25f3c04d55daf70' 
  AND token = 'JAOvFCli82nhomPXS9nHfBzt++mkm4Ei+90CnyFOpzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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