SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd97e38cf78b0d0d27ff91bb414885cf040fa18e9878e565a02b7ddc3ceec19df' 
  AND token = 'BRmQvLK4i0bNsP45T3QuNSfFMRrzO50eZXzS86tLO7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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