SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e96ddf62cb918b52498f44d0aaf32f19539a56c0f0f8d3140640051aa5c9852b' 
  AND token = 'Kp5gjElkebaVLafrL/GIM0Kl+mgTfUDcELUpELw6qJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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