SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5cb175be8708bc32640f6d62273ab0ae1beaeab7ddf8723117b87fca80ab47a' 
  AND token = 'h8zjwe98nBPqpJdILNIkt+xBV7BJlB6uz8WG/31v7kA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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