SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9a158f1b129bd37395662f515ba5d4ce90063597a7de26b81045b98e1ba389b' 
  AND token = 'ahnBPnZ08MWc8+s1jd7sEyHh0Sj8lUcxoIB1VXyN/Nk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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