SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2dcd87fd37b66be7ed16a29812880f04c1cbd49e9d6be84f1614bef25d49c52' 
  AND token = 'dnXvBCmULchEB3IGa+wwjKrkqxL6kHdNgLBrCfwfYiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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