SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '917bcbb2beb179dbe97cc864c4b5d598aab88be3d02807796b084ee2d013fb6f' 
  AND token = 'N7LaRylv+waIRol0SmmMtg1rvvHsfeCL0R7igCcY6f0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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