SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '837af9cb82cad0126fc2ab6323ad706b749542490e67119c084b6d007b5aa3b1' 
  AND token = 'owAReWyb3LQf9JguRqPjIdfpJmziXjIxPptN2SPo2to=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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