SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35e37a3bf62fd7955928f1317d4310fead149474e46dc0e83caae60278468b4a' 
  AND token = 'Ng2KjnL9vscG/6iWNATZizCSmctY1T1otlw3FJuem/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}