SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2caffa751dea6a4b856ac8cc14e2a0db060ccf60b0462764f0551e424f572963' 
  AND token = 'k6r/MkztFPquVrF0+ZLG1F8JjwZcXbZH7iw6GRIFob0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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